1. Field of the Invention
The present invention relates to a recording apparatus which includes rotary members such as a photosensitive drum, as an image carrier, or an intermediate transfer drum.
2. Description of the Related Art
For example, in a full color printer of the electrophotographic type, multicolor toner images are primarily transferred in a sequential manner from the photosensitive drum to the intermediate transfer drum to overlay the respective color images thereon so that a full color image is formed, which is then secondarily transferred onto the recording medium.
In the recording apparatus wherein the above intermediate transfer drum is used, if the distance between the photosensitive drum and the intermediate transfer drum is fixed, a problem occurs in that a difference of color shade may be generated in the primary transfer image by a significant variation in the contacting force within one rotation of both the drums due to a shape error in the intermediate transfer drum (such as eccentricity or a diametric error).
Accordingly, in the prior art, the recording apparatus is adapted so that the axial position of the intermediate transfer drum is movable and the drums are brought into contact under a constant contacting force via a spring or the like.
The secondary transfer of a toner image from the intermediate transfer drum to the recording medium is carried out by press-contacting the recording medium onto the intermediate transfer drum by a transfer roller disposed on the back side of the recording medium in a secondary transfer zone.
The position of intermediate transfer drum, however, inevitably fluctuates due to shape errors (such as eccentricity or deviation from the circularity) during the secondary transfer process, which causes a variation in the contacting force between the intermediate transfer drum and the recording medium and generates an uneven secondary transfer to deteriorate the image quality on the recording medium.